Lighter foods could be key to cutting calories

Action Points

Note that this cross-over cohort study demonstrated that increasing both the energy density and portion size of foods given to 3-6 year olds substantially increased caloric intake.

Be aware that these effects were independent, suggesting that a reduction in either portion size or energy density may lead to decreased caloric intake.

Common foods in preschool children's lunches like chicken, applesauce, and macaroni and cheese are calorie dense but can be manipulated to substantially decrease total caloric intake, according to a new crossover-design trial.

Researchers gave six meals to three childcare centers once a week for 6 weeks and varied the meals by energy density and portion size; they found that energy intake was independently affected by both size and density (both P<0.0001).

Doubling the portions upped energy intake by 24%, according to Barbara Rolls, PhD, at Pennsylvania State University, and colleagues, and increasing energy density by 42% led to a 40% increase in energy intake.

The combined increase of portions and energy density led to an increase of of 175 ± 12 kcal or 79%, with chicken, mac and cheese, and applesauce contributing most to the increase in the study, which was published in Physiology & Behavior.

"Reducing the energy density of foods and beverages should be a priority in developing strategies, since modest changes in energy density have a large impact on intake and are unlikely to be noticed by most children or adults," wrote the authors. "There are several effective strategies to reduce the energy density of meals while maintaining palatability; for example, recipes can be modified by reducing the fat or sugar content or adding water-rich ingredients, including fruits and vegetables."

The effects of portion size and energy density were not affected by the child's weight or age, but it was influenced by the parents' rating of their kid's eating habits. The authors wrote that earlier studies have shown mixed results when it comes to age and weight status affecting response to larger portions, and that overall, energy intake in kids hasn't been well studied.

"Determining how typical variations in the portion size and energy density of a meal influence preschool children's energy intake is essential in order to understand the environmental factors that affect children's food intake and to develop practical strategies to counter these effects," wrote the authors.

The meals were served to children in their classrooms. Across all six meals, all the foods and milk were served at three varying levels of portion size -- 100%, 150%, or 200% -- and two levels of energy density -- 100% or 142%. The children's weight, age, and attitudes toward the food were taken after the last meal and were based on a scale from "super yummy" to "super yucky." Household incomes of the parents were far above average, and in about 90% of families, both parents had college degrees.

Children age 3 to 6 were recruited by letters to their parents, and children with allergies to the foods were excluded. In total, 131 children were enrolled. They were told that they could eat as little or as much as they wanted of the meal in front of them, but that they could not ask for more food. The meal consisted of grilled chicken or chicken nuggets, macaroni and cheese, broccoli or peas, applesauce, ketchup, and milk.

Those foods were chosen because they can vary by energy density, wrote the authors; the chicken nuggets, for example, are far more dense than grilled chicken. The authors added that recipes can be modified by reducing fat or sugar content or adding water-rich ingredients like fruits and vegetables. Children's ratings of the food had no significant affect on the results, but kids who were rated as being more responsive to food by their parents had larger intake when portions were increased.

The authors wrote that since intake was substantially affected by portion size and energy density, "recommendations focusing on these factors should be widely disseminated."

Limitations of the study include a lack of generalizability because of the foods used and the way in which they were served -- many daycare centers serve the foods family style. "Future research should be conducted for longer periods of time on different populations to extend these findings and determine if children adjust for variations in meal portion size and energy density at later meals," wrote the authors.

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